Abstract
Immunoelectrophoretic studies were carried out on plasma samples of 5 young infants with idiopathic vitamin K deficiency and 5 infants with secondary vitamin K deficiency.
Abnormal prothrombin without procoagulant activity was demonstrated by one-dimensional immunoelectrophoresis (Laurell's method) and the Echis carinatus venom prothrombin assay in all of 10 patients with vitamin K deficiency in young infants.
The abnormal prothrombin was distinguished from normal prothrombin in lack of procoagulant activity, disability to bind to barium sulfate, and faster mobility in the presence of calcium ions. Thus, this abnormal prothrombin had the same characteristics as the abnormal prothrombin in coumarin-treated patients.
Abnormal factor IX without procoagulant activity was also demonstrated by the antibody neutralization technic in 7 patients.
In order to study the turnover of the abnormal prothrombin in those patients, two-dimensional immunoelectrophoresis was carried out serially after administration of vitamin K. Although the abnormal prothrombin gradually decreased concomitantly with increase of normal prothrombin after administration of vitamin K, the plasma samples from patients contained small amount of the abnormal prothrombin even in 48 hours after treatment. It was found that the abnormal prothrombin didn't change to normal prothrombin even in the presence of vitamin K in contrast with that in the liver.
Although the plasma of two patients with mild secondary vitamin K deficiency contained abnormal prothrombin as well as normal prothrombin, the plasma of 3 patients with hemorrhagic disease of newborn didn't contain abnormal prothrombin. Thus, the latter may not be only due to vitamin K deficiency, but also due to prematurity of the liver.
